The present invention relates to an anti-rotation device and anti-rotation structure for a pipe and a connector to restrain or prevent a connector, for example, which is adapted for assembly in a gasoline fuel piping of an automobile, from relatively rotating with respect to a pipe which is inserted in and connected to the connector.
In a gasoline fuel piping for an automobile, a connector is used for connecting a pipe and a resin tube as a mating member. For example, the connector comprises a tubular connector housing and a retainer. The connector housing is formed with a tube connecting portion on one axial side and a retainer holding portion on the other axial end of the connector housing. The retainer is received or held by the retainer holding portion. In this structure, a resin tube is fitted to the tube connecting portion, the pipe is inserted in the connector housing through an opening of an opposite axial end of the connector housing or the retainer holding portion to be connected to or snap-fitted in the connector, and thereby the pipe is connected with the resin tube. The pipe to be connected to the connector is formed with an annular engagement projection on an inserting side portion of straight tubular shape to define an inserting end portion. The inserting end portion of the pipe is inserted in the connector housing, the annular engagement projection snap-engages with the retainer or a connecting engagement portion of the retainer, and thereby the pipe snap-fits in the connector or the connector housing.
A sealing member is fitted in the connector housing on one axial side from the retainer holding portion to provide a seal between the connector housing and the pipe inserted therein. The sealing member prevents leakage of gasoline fuel therebetween.
Meanwhile, for example, when a resin tube connected to a connector is continued to a gasoline engine of an automobile, the connector or a connector housing constantly rotates at a small angle with respect to a pipe by vibration transmitted from the gasoline engine to the connector via the resin tube, and thereby a sealing member which is disposed between the connector or the connector housing and the pipe is worn and a sealing property is deteriorated between the connector and the pipe. Therefore, it is preferred to construct an anti-rotation structure in an assembled unit of a pipe and a connector to prevent relative rotational movement of the connector or a connector housing with respect to the pipe.
Then there is a demand for an anti-rotation device for a pipe and a connector to restrain or prevent relative rotational movement of a connector with respect to a pipe. In this connection, for example, the following document 1 discloses an anti-rotating device to be fitted on a pipe and a connector so that one end portion thereof clips flat regions formed on diametrically symmetrical positions on an outer peripheral surface of the connector or a connector housing and U-shaped cutaway formed on an opposite end portion thereof receives therein a bent portion of the pipe formed to be bent with respect to a straight tubular portion of the pipe. By adapting this anti-rotation device, the pipe is connected to the connector in co-rotatable relation, and thereby relative rotational movement of the connector with respect to the pipe may be effectively prevented. And, the following document 2 also discloses another anti-rotation device utilizing a bent portion of a pipe. Further, on the other hand, there are other techniques known to prevent a connector from rotating relatively with respect to a pipe without an independent anti-rotation device. For example, the following document 3 discloses a connector provided with a large opening in a side wall of a retainer holding portion (connecting portion) of a connector housing. According to this disclosure, a pipe is inserted in the connector housing, then, a retainer member of U-shape in cross-section is fitted in the opening, and thereby the pipe is connected to the connector via the retainer member in locking relation against axial movement and in co-rotatable relation. Also the following document 4 discloses a technique that an inner periphery of a connector housing as female member is engaged directly with an outer periphery of a pipe as male member in co-rotatable relation.
Document 1JP, A, 9-269088(specifically page 3, FIG. 1)Document 2JP, A, 2002-213673(specifically page 4, FIG. 3)Document 3JP, A, 2002-276878(specifically page 4, FIG. 1)Document 4JP, U, 3-68695specification and drawings(specifically page 8, FIG. 3)
However, if an anti-rotation device as disclosed in the document 1 or document 2 is adapted, piping design freedom is limited as a connector joining portion should be arranged near a bent portion of a pipe. And, the bent portion should be configured on the pipe with high bending accuracy, for example, with such accuracy as not to allow a portion of the pipe to be received in a cutaway of the anti-rotation device flattened. It is troublesome to configure the bent portion on the pipe with such high bending accuracy.
Also, anti-rotation structure disclosed concretely in the document 3 or 4 does not have sufficient range of applicability as no independent anti-rotation device is applied.
Accordingly, it is an object of the present invention to provide an anti-rotation device which can effectively prevent relative rotational movement of a connector with respect to a pipe by mounting on an assembled unit of the pipe and the connector without utilizing a bent portion of the pipe. It is another object of the present invention to provide an anti-rotation structure for a pipe and a connector adapting such an anti-rotation device. And it is yet another object of the present invention to provide an anti-rotation structure for a pipe and a connector which can effectively prevent relative rotational movement of a connector with respect to a pipe without utilizing a bent portion of the pipe, and has sufficient application flexibility.